$BTC
Bitcoin can be exchanged for cash just like any asset. There are numerous cryptocurrency exchanges online where people can do this but transactions can also be carried out in person or over any communications platform, allowing even small businesses to accept bitcoin. There is no official mechanism built into bitcoin to convert to another currency.
Bitcoin was created as a way for people to send money over the internet. The digital currency was intended to provide an alternative payment system that would operate free of central control but otherwise be used just like traditional currencies.